TORONTO -- A Toronto-area constable who was secretly investigated in an undercover corruption probe was found guilty Wednesday of 11 offences, including trafficking cocaine and steroids and inappropriately searching and disclosing confidential information.

Richard Senior was arrested as part of a broader corruption probe in October 2018 and originally faced 30 charges, though more than half were dropped at the start of the trial.

In a virtual ruling Wednesday, Ontario Superior Court Justice Vanessa Christie detailed Senior's 11 offences, while acquitting the officer on three other charges.

Senior wrote and submitted an intelligence report on his mistress that falsely attributed the information to a confidential source after their affair was exposed, then took $300 dollars he was given as a payment for that source, Christie found.

He also conducted several illegitimate searches in a police database, including looking up a licence plate to help an undercover officer posing as an informant steal drugs, and finding information on a friend's ex-boyfriend as a personal favour, the judge ruled.

"Const. Senior knew that (the undercover officer) wanted this information to 'rip' drugs from a rival drug dealer. (The undercover officer) said this explicitly to Const. Senior several times," Christie said in her decision.

The longtime York Regional Police officer also trafficked steroids to another undercover officer posing as his partner by acting as a go-between for him and the seller, she found, noting Senior "made it possible for a sale to occur that could not otherwise have taken place."

Senior also stole a police shotgun as part of a plan to rob a fictitious drug warehouse he heard about from the undercover officer acting as an informant, Christie said in convicting him on two weapons-related charges. Furthermore, he sought to sell the cocaine he expected to steal from the warehouse to the undercover officer acting as an informant and another man.

The officer was acquitted, however, of attempted robbery because Christie found the plan had not moved past the preparation stage into concrete action, which is required for a conviction. She pointed to the fact that no date had been set for the robbery as a sign that it remained a plan rather than an attempt.

"It is the view of this court that Const. Senior intended to commit the robbery. Const. Senior's detail-oriented efforts and utterances demonstrate his intention to carry out the robbery, and he took numerous steps in preparation toward that goal," she wrote.

"However, an attempt requires more -- a step in carrying out that intent which amounted to more than mere preparation. In other words, all preparation must be complete. There must be a step in the commission of the offence."

Senior was also cleared on a charge of trafficking steroids to another officer because the judge said the evidence was unclear as to what actually happened and what substance, if any, was provided.

The constable was further acquitted on another charge of breach of trust related to an incident in which he warned another man that he was the subject of a police investigation. Christie found there was insufficient evidence to find that Senior acted "with the intention to use his public office for a purpose other than the public good."

During trial, Senior's lawyers argued none of the incidents that spurred the charges would have happened without the "instigation" of police, who had launched a secret investigation into his actions.

They also argued Senior didn't mean to act dishonestly but simply lacked training on police procedures related to dealing with informants.

The defence is expected to bring forward an application on entrapment, to be heard in late June.

The two undercover officers, whose identities are protected under a publication ban, testified during the trial.

Senior did not, but court heard recordings and viewed transcripts of his conversations and messages with the undercover officers and others.

This report by The Canadian Press was first published April 21, 2021.